These are enemy generators, and most be destroyed as soon as possible. Spheroids spawn 1 to 6 Enforcers, and Quarks spawn 1 to 6 tanks. If a player dies and a quark or spheroid remains, upon re-initiation of the wave, the spheroid or quark can spawn an additional 1 to 6 enemies again. This can create the deadly “steady state” condition where a play can kill many enemies on a screen, but failing to kill the enemy generators, the player will face the same number of enemies again and again after dying, making almost no progress on the wave. In such a deadly cycle many player lives can be lost in succession. It is especially crucial in tank waves to destroy spawning quarks immediately.